This invention generally relates to a safety latch assembly for a panel board, and more particularly to a safety latch assembly for use with a circuit breaker panel board to prevent either the opening or closing of the panel cover when any of the breakers are in the ON position.
The panel board to which the present invention relates is of the type used in hazardous location, such as in the presence of flammable vapors, liquids or gases or combustible dusts, easily ignitable fibers or flyings, damp or wet locations, or the like.
While safety latch assemblies for panel boards are generally known in the art, they have certain disadvantages. Many are relatively complex and expensive and not easily adaptable to standard safety panel design, and they permit closing of the closure cover with the breaker in the ON position. This latter disadvantage can result in the breaker being ON with the external handle assembly for operating the breaker indicating that the breaker is in the OFF position resulting in a potentially hazardous condition.
Thus, it is a primary purpose of the present invention to provide a safety latch assembly that is relatively simple in construction, inexpensive, exceptionally reliable, and readily adaptable for use with existing safety breaker panels.
It is a particular objective of the invention to provide such a safety latch assembly that prohibits closing of the closure cover with the breaker in the ON position, and preferably prevents both closing and opening of the closure cover with the breaker in the ON position.
Generally, the panel board safety latch assembly of the present invention is used with a circuit breaker panel board including a cabinet or enclosure in which one or more circuit breakers are mounted behind a panel member. Typically, several such breakers are mounted in columns and each is operable between ON and OFF positions by an actuating member such as a toggle. A handle is mounted in the cover of the cabinet for operable engagement with the actuating member to operate same between its ON and OFF positions.
The safety latch assembly of the present invention includes a movable member operable in response to movement of the actuating member and which has means engaging a portion of the handle mechanism to prevent engagement of the actuating member by the handle mechanism, and thus closing of the cabinet cover, when the breaker is in the ON position. The safety latch assembly of the present invention also includes means engaging the handle mechanism when the actuating member is in the ON position preventing disengagement of the handle mechanism and actuating member, and thus opening or removal of the cover. A more detailed description follows.